Piston arrangement for work transmitting machine

ABSTRACT

A PISTON ASSEMBLY INCLUDES A TWO PIECE PISTON HEAD HAVING A RING RETAINING SECTION AND A SKIR SECTION. FASTENING MEANS WHICH ARE ACCESSIBLE FROM THE LEAD FACE OF THE RING RETAINING SECTION HOLDS BOTH SECTIONS TOGETHER IN FACE TO FACE CONTACT IN SUCH A MANNER THAT THE RING RETAINING SECTION CAN BE DETACHED AND REMOVED FROM THE CYLINDER WITHOUT THE NECESSITY FOR REMOVING THE SKIRT SECTION. A ROTATION PREVENTION MEANS IS MOUNTED BETWEEN THE FASTENING MEANS AND THE TWO PISTON HEAD SECTIONS. THE OPPOSITE END   OF THE FASTENING MEANS IS ADAPTED FOR SECUREMENT TO A CONNECTING ROD.

Oct. 5, 1971 w, F, L 5, JR 3,610,111

nswou ARRANGEMENT won wonx wmusmmme MACHINE s Sheets-Sheet 1 Filed 00%. 16, 1969 35' Fink-22 Oct. 5, 1971 w, m s, JR 3,610,111

PISTON ARRANGEMENT FOR WORK TRANSMITTING MACHINE Filed Oct. 16, 1969 3 Sheets-Sheet 2 Oct. 5, 1971 3,610,111

PISTON ARRANGEMENT FOR WORK TRANSMITTING MACHINE W. F. DILKS, JR

3 Sheets-Sheet 5 Filed 001,. 16, 1969 United States Patent US. Cl. 92-190 11 Claims ABSTRACT OF THE DISCLOSURE A piston assembly includes a two piece piston head having a ring retaining section and a skirt section. Fastening means which are accessible from the lead face of the ring retaining section holds both sections together in face to face contact in such a manner that the ring retaining section can be detached and removed from the cylinder without the necessity for removing the skirt section. A rotation prevention means is mounted between the fastening means and the two piston head sections. The opposite end of the fastening means is adapted for securement to a connecting rod.

BACKGROUND OF THE INVENTION This invention relates to a piston design wherein the piston rings may be replaced without removing the engine from, for example the forklift truck or other machine, and without removing the piston and connecting rod from the engine. Various attempts have been made to provide a piston wherein the piston rings are secured on a removable section of the piston head. Examples of such attempts are described in US. Pats. 3,388,915; 3,218,939; 3,181,429; 3,108,514; 2,731,315; 2,566,944; 2,460,948; and 1,977,075. Such attempts have not proven successful for a number of reasons. It is essential, for example, in providing such a removable section that the lead face of the piston head be free from protrusions or other obstructions which will interfere with the proper compression ratio. Additionally, care must be taken to assure a secure attachment of the piston head sections and the connecting rod. Moreover provisions must be made to permit drainage of the oil in the cylinder.

SUMMARY OF THE INVENTION An object of this invention is to provide a piston assembly wherein the piston ring retaining section is readily detachable.

A further object of this invention is to provide such a piston assembly which is usable in tow motors of forklift trucks and other low speed engines such as pumps and air compressors.

In accordance with this invention a piston assembly includes a two piece piston head having a ring retaining section and a skirt section. Fastening means which are accessible from the lead face of the ring retaining section, hold both sections together in face to face contact in such a manner that the ring retaining section can be detached and removed from the cylinder without the necessity for removing the skirt section. The opposite end of the fastening means is adapted for securement to a connecting rod.

The fastening means may be a retaining member which includes a threaded rod extending through both the skirt and ring retaining sections and terminating in a recess in the leading face of the ring retaining section so that a nut or other suitable fastener may be secured thereto in the recess.

Mating oil grooves may be provided in the following face of the ring retaining section and the front wall of the skirt section to provide a means of communication 'ice with an oil ring retaining groove in the ring section and the hollow interior of the skirt.

The retainer may be U-shaped at its lower end with a pair of flat faces abutting against bosses in the skirt for receiving a pin by means of which a connecting rod is sccured to the unit.

A key may be provided in a key way and slots in the retainer rod and both the skirt and ring retaining section to assure alignment of the oil grooves and to prevent relative rotation of the parts.

THE DRAWINGS FIG. 1 is an elevation view of a piston arrangement in accordance with this invention, mounted in an engine block;

FIG. 2 is an exploded view of the piston arrangement shown in FIG. 1;

FIG. 3 is a cross-sectional view of the piston arrange- I ment shown in FIGS. l-2;

FIG. 4 is a cross-sectional view taken through FIG. 3 along the line 44; and

FIG. 5 is a cross-sectional view taken through FIG. 4 along the line 5-5.

DETAILED DESCRIPTION FIG. 1 shows a conventional engine block 10 which includes for example an intake manifold 12 having a valve 14 in the fuel line 16 and a head 18 upon which is mounted a plurality of spark plugs 20. Engine block 10 also includes cylinder 22 and connecting rod 24 secured to crankshaft 26 with an oil pan 28 secured at the bottom of the engine block. The movement of the connecting rod which is transmitted to the crankshaft is obtained by its connection to the novel piston 30 which is formed in accordance with this invention.

Although a particular engine block 10 is illustrated in FIG. 1 the piston arrangement 30 can be incorporated in cylinders of other work transmitting machines such as stationary engines or mobile equipment that operate around the clock at relatively low speeds, for example pumps, air compressors, and forklift trucks or any type of internal combustion engine.

As shown in FIG. 2 the novel piston arrangement 30 includes a piston head formed in two parts; namely, the ring retaining section 32 and the skirt section 34. These parts are held together by a retainer 36 which in turn receives a wrist pin 38 upon which the connecting rod 24 would be mounted. A nut 40 is secured to the threaded end of retainer 36 while the parts are held in alignment by a key 42. A pair of keepers 44, 44 are also provided for the wrist pin 38.

The parts are assembled together in the following manner. The threaded rod 46 of retainer 36 is inserted up through the bottom of skirt section 34. The piston pin is then inserted through opening 48 in skirt section 34 and opening 50 in retainer 36. Connecting rod 24 is mounted over piston pin or wrist pin 38 and the wrist pin is inserted through opening 52 of retainer 36. Keepers 44 are then inserted in openings 48, 54 of the skirt section 34 to maintain the wrist pin in position. Ring retaining section 32. is then positioned over threaded rod 46 and the parts are held in alignment by key 42 and held together by nut 40. The positioning of ring retaining section 32 can be performed either before or after the piston rod assembly is installed in the motor.

FIGS. 3-5 show the various parts assembled in cylinder 22 and show other structural details of the parts. For example as indicated therein ring retaining section 32 includes a flat leading face 56 and a flat following face '58. As later described an enlarged recess 60 and a pair of threaded holes 68 are provided in the top or leading face 56, while a plurality of peripheral grooves 61 are provided in the side wall of ring retaining section 32-for holding any suitable number of compression rings. Adjacent to following face 58 is a further peripheral groove '64 which holds oil ring 66. Communicating with oil ring groove 64 is a pair of half moon shaped openings or pockets 70 which mate with half moon shaped grooves 72 extending through the fiat top Wall 74 of skirt section 34. These half moon shaped grooves or pockets 70, 72 provide a passageway for oil drainage from ring 66 to the interior of cylinder 32. Accordingly, it is essential that these grooves be aligned and that there be no relative rotation of skirt section 34 with respect to ring retaining section 32. The proper alignment is obtained by the inclusion of key 42 which fits into key way 76 of rod 46 and slots 78, 80 in ring retainer 32 and skirt section 34 respectively (see FIG. 4). In its assembled form (as shown in FIG. 3) key 42 is maintained in the key way 76 by its abutment against nut 40.

As indicated in FIGS. 3 and skirt section 34 is hollow having flat front wall 74 with a peripheral skirt 82. A pair of diametrically opposed bosses 84 are integral with skirt 82 and are bored having openings 48, 54 therein. The bottom of front wall 74 also includes a recess 86- for receiving retainer 36.

As also indicated in FIGS. 3 and 5 retainer 36 has a threaded rod 46 at one end and terminates in a U shaped member which includes a pair of flat walls or flanges 88 joined by arcuate sides 100 and a top wall 90. Openings 50, 52 are disposed through flanges 88, 88. Wall 90 includes a recess 92 and a boss 94 which fits in recess 86 of skirt section 34. The recesses 92 permits sufficient clearance for pivotal movement of connecting rod 24 while the boss 94 permits the top wall 92 to have substantially uniform thickness through substantially all of its length. The inclusion of flanges 88 are advantageous in that the flanges 88 add strength to the retainer 36 to resist the pulling force from wrist pin 38 and connecting rod 24. In this respect if flanges 88 were not provided the resistance caused by rings 62 against the inner surface of cylinder 22 upon a downward pull by connecting rod 24 would be so great that there would not be enough material in retainer (i.e. top wall 90 alone would be too thin) that the threaded rod 46 would be pulled completely through the openings 96, 98 in skirt section 34 and retaining section 32, respectively, whereby the retainer 36- would no longer function as a fastener. Flanges 88, 88, however, provide suflicient strength to retainer 36 to prevent this from happening.

In its assembled form, all of the parts fit snugly together with flanges 88 abutting against bosses 84 (FIG. 5) and with the intermediate arcuate sides 100 received in a corresponding recess in skirt section 34.

As previously indicated leading face 56 of ring retainer 32 is substantially flat but includes central recess 60 and threaded openings 68. Recess 60 is of suflicient depth that nut 40 can be threaded on to rod 46 of retainer 36 and be fully received within the recess 60 while rod 46 terminates flush with or below leading face 56, so that no protrusions or obstructions extend from this flat face which would otherwise interfere with the proper compression ratio.

Advantageously, positive locking means are provided on threaded rod 46 in addition to the threaded engagement of nut 40 with rod 46. The purpose of this additional positive locking means is to avoid the necessity of tightening the nut to such an extent that rod 24 would bend. FIG. 2 shows one form of positive lockingv means wherein an elastic ring 102 is disposed in the threaded opening of nut 40. Other suitable positive locking means may also be used such as a cotter pin or a nut having peripheral longitudinal slits at its upper end.

The provision of threaded opening 68 in leading face 56 permits the ring retaining section 32 to be quickly and conveniently removed. In this regard after nut 40 is unscrewed from rod 46- by for example the manipulation of a socket wrench in recess 60, a T handle puller or any other suitable tool can be engaged with the openings '68 and the ring retaining section then simply removed. Withring retaining section 32 thus removed the rings can be readily replaced without a complete disassembly of the engine block. The only portion of the engine block which must be removed is head 18 to render the ring retaining section 32 accessible.

What is claimed is:

1. A piston arrangement for a work transmitting machine comprising a piston head, said head including a ring retaining section and a skirt section adapted for sliding action in a cylinder, said ring retaining section having a leading face and a following face joined by an intermediate peripheral wall, a plurality of ring receiving grooves in said peripheral wall, said skirt section being hollow and having a front wall with a depending skirt and an open bottom, fastening means detachably securing said ring retaining section and said skirt section together with said following face and said front wall in face to face contact, said fastening means being de tachable by manipulation thereof from said leading face of said ring retaining section whereby said ring retaining section may be detached from said skirt section and removed from the cylinder to replace rings thereon without the necessity for removing said skirt section from the cylinder, securing means on said fastening means remote from said leading face for securement to a work transmitting member, said fastening means including a rod extending through said skirt section and said ring retaining section, a shoulder on said rod abutting against said skirt section, a recess being in said leading face of said ring retaining section, said rod terminating in said recess, locking means on said rod in said recess spaced from the Walls of said recess, said rod is coaxial with said sections, aligning means preventing relative r0- tation of said sections, said aligning means including a key, a key way being in said rod, aligned slots being in each of said ring retaining section and said skirt section, said key being in said key way and said slots, and said locking means abutting against said key.

2. A piston arrangement as set forth in claim 1 wherein oil drainage means are in said following face of said ring retaining section and said front wall of said skirt section communicating with one of said grooves in said peripheral wall.

3. A piston arrangement as set forth in claim 1 including removal means on said leading face to facilitate the removal of said ring retaining section after said fastening means have been detached.

4. A piston arrangement as set forth in claim 1 wherein said fastening means includes a pair of apertured flanges disposed in said skirt section.

5. A piston arrangement as set forth in claim 1 wherein said rod is threaded, said locking means including a threaded nut threadedably engaging said rod, and positive locking means upon said rod.

6. A piston arrangement as set forth in claim 4 wherein said fastening means includes a top wall connecting said flanges to each other and to said rod, and a recess being in said top wall disposed toward said open bottom of said skirt section.

7. A piston arrangement as set forth in claim 6 wherein said top wall of said fastening means includes a boss disposed opposite said recess.

8. A piston arrangement for a work transmitting machine comprising a piston head, said head including a ring retaining section and a skirt section adapted for sliding action in a cylinder, said ring retaining section having a leading face and a followng face joined by an intermediate peripheral wall, a plurality of ring receiving grooves in said peripheral wall, said skirt section being hollow and having a front wall with a depending skirt and an open bottom, fastening means detachably securing said ring retaining section and said skirt section together with said following face and said front wall in face to face contact, said fastening means being detachable by manipulation thereof from said leading face of said ring retaining section whereby said ring retaining section may be detached from said skirt action and removed from the cylinder to replace rings thereon without the necessity for removing said skirt section from the cylinder, securing means on said fastening means remote from said leading face for securement to a work transmitting member, including aligning means for preventing relative rotation of said ring retaining section with respect to said skirt section, including removal means on said leading face to facilitate the removal of said ring retaining section after said fastening means have been detached, said fastening means including a rod extending through said skirt section and said ring retaining section, a recess being in said leading face of said ring retaining section, said rod terminating in said recess, locking means being on said rod in said recess, said fastening means including a pair of apertured flanges disposed in said skirt section, said aligning means including a key, a key way being in said rod, aligned slots being in each of said ring retaining section and said skirt section, said key being in said key way and said slots, said locking means abutting against said key, said rod being threaded, said locking means including a threaded nut threadably engaging said rod, positive locking means upon said rod, said fastening means including a top wall connecting said flanges to each other and to said rod, a recess being in said top wall disposed toward said open bottom of said skirt section, said top wall of said fastening means including a boss disposed opposite said recess, said skirt section including a pair of diametrically opposed internal bosses having apertures therethrough, and said flanges being disposed against said internal bosses with the apertures in said internal bosses and said flanges being aligned.

9. A piston arrangement as set forth in claim 8 wherein a pin is disposed in said apertures of said internal bosses and in said apertures of said flanges, and said apertures of said bosses being closed by keepers disposed in said skirt.

10. A piston arrangement as set forth in claim 9 including a pair of half moon shaped oil drainage grooves in each of said following face and said front wall.

11. A piston arrangement for a work transmitting machine comprising a piston head, said head including a ring retaining section and a skirt section adapted for sliding action in a cylinder, said ring retaining section having a leading face and a following face joined by an intermediate peripheral wall, a plurality of ring receiving grooves in said peripheral wall, said skirt section being hollow and having a front wall with a depending skirt and an open bottom, fastening means detachably securing said ring retaining section and said skirt section together with said following face and said front wall in face to face contact, said fastening means being detachable by manipulation thereof from said leading face of said ring retaining section whereby said ring retaining section may be detached from said skirt section and removed from the cylinder to replace rings thereon without the necessity for removing said skirt section from the cylinder, securing means on said fastening means remote from said leading face for securement to a work transmitting member, said securing means including a pair of apertured flanges disposed in said skirt section, said skirt section including a pair of diametrically opposed intemal bosses having apertures therethrough, and said flanges being disposed against said internal bosses with the apertures in said internal bosses and said flanges being aligned.

References Cited UNITED STATES PATENTS 1,460,041 6/1923 Smith 92128 1,463,245 7/1923 Bolan 92189 1,482,675 2/1924 Childers 92190 X 1,693,280 11/1928 Leary 92189 1,900,991 3/1933 Matheson 92189 2,126,627 8/1938 Fiedler 92189 2,323,310 7/1943 Clark 92186 X 2,398,577 4/1946 Bratzel 92--160 2,409,852 10/1946 Harrah 92160 2,671,704 3/1954 Brown 92189 FOREIGN PATENTS 871,646 1/1942 France 92191 86,114 8/1957 Netherlands 92258 MARTIN P. SCHWADRON, Primary Examiner r l. C. COHEN, Assistant Examiner US. Cl. X.R. 

